This invention relates generally to apparatus and methods for concrete manufacturing and, more particularly, to such apparatus and methods in which the concrete includes a fiber ingredient.
Referring to FIG. 1, the prior art system of manufacturing concrete with steel fiber additive 10 includes a cement/flyash silo 12 with a dump drum 14, an aggregate bin assembly 16 with a scale 18 and an aggregate hopper assembly 20 all resting on a generally flat section of ground or floor 22. The aggregate hopper assembly 20 includes three compartmental sections for separately receiving through open tops 20A and capable of separately holding three different types of aggregate, such as CA-7 coarse, A-2 fine, rocks and sand. After the aggregate is loaded by front loaders in through the tops of the compartmental sections, selected amounts are allowed to fall through individual gate controlled openings in the bottom 20B of the aggregate hopper assembly 20 onto three underlying, parallel, aggregate belt conveyors 24, respectively. The three conveyors 24 separately convey from the three separate aggregate hoppers from the bottom 20B to the tops 16A of the compartmental sections of the aggregate bin assembly 16.
The amount of aggregate in each of the three compartmental sections is weighed by the associated scales 18 and selected amounts are then passed to the bottom of a mixed aggregate belt conveyor 26. The conveyor 26 receives aggregate from any and all of the selected compartmental sections of the aggregate bin assembly 16, and the aggregate from the different compartmental sections are dumped together on the one conveyor 26. The aggregate mix on the conveyor 26 is conveyed to an aggregate inlet 14A of the dump drum 14. In addition a selected amount of cement/flyash mixture is allowed to pass into a cement/flyash inlet 14B of the dump drum 14 by gravity feed through a chute 28.
The mixture of the selected amount of cement/flyash and the weighed and selected amounts the three possibly different types of aggregate are then mixed in the dump drum during rotation of the drum. Water is then added into the drum 14 from the water feed tube 14C from water source 14D to be mixed with the dry aggregate. After this wet concrete mixture has been blended in the dump drum 14, it is available to be gravity feed loaded from the dump drum 14 into a succession of dump trucks 27 for conveyance of the mixed wet concrete to another site.
In the case of the dry concrete recipe or formula calling for the inclusion of steel fibers, the steel fibers are packaged in bags 30 weighing approximately forty pounds that are delivered to the site and are manually opened, lifted and hand dumped onto the aggregate belt conveyor 26 from a platform. Alternatively, the bags are manually dumped onto one of the three aggregate conveyors 24 for conveyance to the conveyor 26, or onto a separate fiber conveyor 32 for conveyance via the aggregate bin assembly 16 and the aggregate belt conveyor 26 to the dump drum 14. In the case of the preparation of premixed concrete on site, the dry concrete formula apart from the fiber additive is delivered into a premix cement truck (not shown) without mixing in the dump drum 14, and a separate, special additive conveyor (not shown) is used to move the fiber additive to a load receiving opening of the cement truck into which the other ingredients are also received. The forty pound bags of additive 30 are opened manually and manually dumped onto this special additive conveyor.
The present inventors have determined that this process of manufacturing concrete with fiber additive is disadvantageously labor intensive, inefficient and wasteful of material due to breakage of the forty pound bags of fiber additive and spillage during manual handling and dumping of the bags.